Final answer:
To form BaCO₃ precipitate, mix aqueous solutions of barium chloride (BaCl₂) and sodium carbonate (Na₂CO₃); the reaction will produce insoluble barium carbonate and sodium chloride in solution.
Step-by-step explanation:
To form BaCO₃ as a precipitate in an aqueous reaction, two reactants that provide the necessary ions, barium (Ba²⁺) and carbonate (CO₃²⁺), are required. A suitable barium-containing reactant would be barium chloride (BaCl₂), and a good source of the carbonate ion would be sodium carbonate (Na₂CO₃). When these two solutions are mixed, the reaction that occurs is:
BaCl₂ (aq) + Na₂CO₃ (aq) → BaCO₃ (s) + 2 NaCl (aq)
This reaction demonstrates that barium ions and carbonate ions combine to form barium carbonate, which is insoluble in water and thus precipitates out of solution. To maximize the yield of BaCO₃ precipitate, it is essential to mix stoichiometrically equivalent amounts of the reactants based on their molar ratios.